Automatic power transmission means



0ct. 28, 1941. B BURNS 2,260,795

AUTOMATIC POWER TRANSMISSION MEANS A Filedf Jan. 30, 1959 5 Sheets-Sheet 1 H @ma me H R 2 Hfen/s i,

l F012 THE FM A A TroRA/EYS Oct. 28, 1941. B. BURNS f AUTOMATIC POWER TRANSMISSION MEANS Filed Jan. so, 1959 5 sheets-sheet 2' /NVE/vroR, BRUCE BUR/v5 @Y HARR/J, K/ECH F T c HARR /6 Oct. 2,8, 1.941.

B. BURNS AUTOMATIC POWER TRANSMISSION MEANS Filed Jan. so, 1939 5 sheets-sheet s 6 PVN mw MB W@ U @Y ARR/s K/ECH) Oct, 28, 1941.

B BURNS AUTMATI C POWER TRANSM I S S `ION MEAN Sy Filed Jan. so, i939 HOME POWER,

MILES PER HOUR AND L55 IN TOEQUE o 0 /oqo zooo sono 4ooo v RPM ENG/N5 TbRQL/ a HP vs ENGINE :Paso AND ROAD .SPE-ED 'KJ ENGINE SPEED /NVE/v Toe, BRUCE BUR/v5 @Y HA RIAP/5J K/EcH, F a. HARR/ FDR 7715 FIRM A T Toa/Veys 0d.y 28, 1941. B. BURNS 2,260,795

. AUTOMATIC POWER TRANSMISSION MEANS Filed Jam.y 5o, 1959 5 sheets-sheet 5 Foa THE F/RM A TTOQMEYS Patented Oct. 28, 1941 UNITED STATES' PATENT oFrlcE- autres' AUTOMATIC rowna TRANSMISSION misas Bruce Burns, Santa Monica, Calif., assignor to Salslmryvv Corporation, Inglewood, Calls., a corporation ci Caliiiornia Application .Valium 39, 1,939, Serial N0. 253,55?

1o claims.

. power transmissionmeans for a motor vehicle which is adapted to automatically change the effective transmission ratio as the speed ofthe vehicle changes.

Another object is to provide a power transmission for a motor vehicle which is adapted to increase the ratio of engine speed to wheel speed when engine torque increases.,

. Another object of the invention is to provide a power transmission for a motor vehicle which permits adjustment of the effective transmission ratio by the operator to suit his individual needs.

Still another object is to'provide an automatic power transmission whichis cheap to construct in large quantities, which is eillcient and convenient to operate, which requires s minimum of attention, and which is of long life.

These and other apparent objects I attain in a manner which will' be clear from a consideration of the following description taken in connection with the accompanying drawings, in which Fig. 1 is an elevational view of the power plant.

Fig. 2 is an elevational view of the power plant shown in Fig. 1, taken from the opposite sidethereof.

Fig. 3 is a cross-sectional view of the automatic power transmission apparatus forming a part of the power plant shown in Fig. l.

Fig. 4 is a sectional view of a portion of the apparatus of Fig. 3 taken along the line 4 4 in the direction indicated by the arrows.

Fig. 5 is a sectional view of av portion of the apparatus of Fig. 3 taken along theline 5 5 in the direction indicated by the arrows.

Fig. 6 is a sectional view of a portion of the apparatus of Fig. 3 taken along the line 0 0 in the direction indicated by the arrows.

Fig. 7 is a partial view oi the apparatus of Fig. 3 from above, as indicated by the arrow 1.

Fig. 8 is a sectional view of a portion of the apparatus of Fig. 3 taken along the line 0 0 in the direction indicated bythe arrows.'

` Fig. 9 is a sectional view of a portion of the apparatus of Fig. 3 taken along'the line 0 0 in the direction indicated by the arrows.

Fig. 10 is a diagrammatic illustration showing, for one adjustment oi the apparatus, the position of the belt under idling condition.

Fig. 11 is a diagrammatic illustration showing the beltin extreme low gear position.'

Fig. 12 -is a diagrammatic illustration showing the belt in the extreme high gear position.

(Cl. 'isp-2Std?) the belt in an intermediate position under conditions in which the vehicle is being moved forwardly before the engine has started.

Fis. 14 is a chart illustrating the performance characteristics of the apparatus of my invention. Fig. l5 is a chart illustrating-the perfomance l vcharactei'istics of the apparatus of my invention.

Fig. 16 is a cross-sectional View of an alternative form of the countershait unit of my apparatus.

My invention is adapted to drive a single centrai wheel 36 of a vehicle as shown in Fig. l. This wheel is driven by a sprocket 52 which is driven- The construction and operation of the autou matic power transmission means of my invention will now be considered. The crankshaft of the engine 4| projects from a bearing boss |00 n the side oi the crankcase |0| of the engine ai, and carries a hub |02 and a housing |63 which are preferably welded together. A pair of diametrically opposed flat faces |04 milledon the extended end of the crankshaft engages mating iiat surfaces in the end of the hub |02 in such manner that the crankshaft 44 and the hub |02 are rotatively keyed together. A nut |05 engages threads on the extended end of the crankshaft it and, acting through a washer |06, holds the hub |02 firmly in place on the crankshaft 44.. Freely' iournaled` on the cylindrical outer vsurface of the hub |02, with suitable end clearance, is a bushing |01 which is pressed into and carries a tubular pulley hub |08. An inclined pulley face ||0 is welded -to the exterior of the pulley hub |08.

The member III is driven from the shaft 44 through the clutch mechanism 45 shown, which forms no 'part of the present invention and will not be fully described. It will be sumcient to say that this" clutch operates automatically.

Another inclined pulley face opposed to the pulley face lll is adapted to slide and rotate on the pulley hub |08 and for this purpose the pulley face is welded on a sleeve 2 within which are pressed a pair of spaced, hardcned steel bushings ||3 which slide on the hardened and ground exterior surface of the pully hub |00. 'I'hree posts ||4 are riveted to the pulley face at circumferentially rspaced locations,

and through a hole in each of these posts a spring Ill passes and is anchored so as to' permit it to oscillate in a plane parallel to the axis of the unit Il, but to be retained against the action of centrifugal torce. consist of loops of wire pivotally connected at one end to the posts H4 and at the other end Fig. 13 is a diagrammatic illustration showing 60 connected in a similar manner to posts III which The springsV Il! preferably are riveted to a dish-shaped housing Hl. The housing lil is formed with a series of circumferentially spaced keys H which engage corresponding slots |20 in the end of the pulley -hub |05 and are held in place by a snap ring |2| engaging a groove on the pulley hub |06. Compression type helical coil-springs |22 and |23 surround the pulley hub |08 and are. compressed between the housing and the pulley face thus urging the pulley face toward the pulley face H0 at all times. It is apparent that the pulley face is axially movable relative to the pulley face |||i and the housing Hl, but is constrained to rotate therewith by reason of the torque link springs |5.

In the operation of the unit e5, that part oi the apparatus lying between the housing |53 and the member l'il serves primarily to permit starting of the engine il by simply-moving the vehicle forward. In lightweight two-wheel land three-Wheel vehicles of the type to which transmissions of the character of that herein disclosed are most readily applicable, it is often inconvenient and expensive to provide conventional electric starting mechanisms, and it is usually inconvenient, if not undesirably expensive, to provide kick starters or hand cranks. The apparatus of my invention thus overcomes the inherent disadvantages of the above mentioned types of starting through provision of the overruiming clutch starting mechanism described above.

As illustrated in the drawings, the engine is considered to rotate in a clockwise direction as viewed from the right side in Fig. 3. it is apparent that forward motion or" the vehicle with f the engine stationary, therefore, results in similar clockwise rotation of the pulley face |50 under the iniluence of the V-belt 4i. rThe inclined teeth |38 are, therefore, moved in a clockwise direction. Since the friction material |43 is held with the housing |03 until a suiciently great frictional force between material |43 and housing |03 is produced to cause rotation of the housing |03, hub ||l2-and crankshaft 44 of the engine di. Continued rotation of the engine crankshaft causes the engine to start.

After the engine has started, if the pulley face IIU be moving slowly, as is usually the case, the engine even at'idling speed will rotate faster than does the pulley assembly, with the result that the inclined surfaces of the teeth |4| will be rotated out of engagement with the inclined surfaces of teeth |38 and the radial ends of teeth |4| will engage the ends of teeth |38. This leaves the force of the marcel spring |44 as the only force tending to maintain the frictional connection between the material |43 and housing |03. This force is small compared to that required to transmit the torque necessary to move the vehicle, so, with the vehicle stationary, the engine is permitted to idle freely, restrained only by the veryslight braking effect caused by contact of the friction face |43 with the housing |03 under the small axial force of the marcel spring cesan-fc5 Not only does the above described starting mechanism permit starting the engine by pushing the vehicle forward, but it also insures against the engine stalling when the centrifugal clutch is disengaged while the vehicle is still moving forward under its momentum, for under these conditions the vehicle will drive the engine through the inclined teeth |38 and |4|.

This mechanism also acts as an overrunning clutch to permit the vehicle to be pushed back- Ward freely Without rotating the engine, which is often of advantage in maneuvering in close quarters. When the vehicle is moved backwardly the inclined teeth |38 will be rotated in a counterclockwise direction as viewed from the right in Fig. 3 and the radial faces of the teeth |38 and EM will engage, causing the member M6 to be rotated in counterclockwise direction also. The frictional force between the friction face M3 and the housing |53, being the result or" only the axial force of the marcel spring |134, is insucient to transmit any considerable amountof torque, so for all practical purposes the engine is left free to idle or remain stationary while the vehicle is moved backward.'

Following starting of the engine as described above, the unit 45 is adapted through a centriugal clutch action to automatically connect the engine to the pulley ||il||| to drive the vehicle when the speed of the engine exceeds a certain predetermined value.

The automatic clutch unit 45 drives the countershaft unit 46 through the V-belt 4l, the two units 45 and 46 comprising an automatic transmission adapted to vary the effective transmission ratio as the vehicle speed changes, the ratio of engine speed to wheel speed being high for low speeds of the vehicle and being decreased as the vehicle speed increases. The countershaft unit #i6 is mounted on the countershaft 48 which is supported in the bearings 50 retained in the wheel housing 4B, and is restrained against motion along its own axis by a nut |50 bearing against the sprocket 5| at one end of the wheel housing and by a snap ring |5| and a shroud |52 cooperating with a groove in the countershaft at the other end of the wheel housing. On the end of the countershaft 48 is mounted a pulley face and housing member |53, a. disc |54, a hub |55, and a sleeve |56, all welded into one unit. The hub is fitted to the countershaft 48 and is rotatively connected thereto by a key |51 which is positioned in a diametric slot in the countershaft 4B the end of the key |51.v The rightward travel of the key |51 in turn is determined by the adjustment of a screw |59 in threaded engagement with the shaft 48 and-bearing against the key |51.

An axially movable inclined pulley face |6| Vis opposed to the pulley face |53 so as to cooperate therewith in providing inclined contact surfaces forthe belt 41, and is piloted on the sleeve |56 by the inner tubular portion of an annular ramp |62 which is attached to the pulley face |6| by bending over the end portion |63 thereof. I A cylindrical cage |64 is piloted on the countershaft 48 adJacent the snap ring |5| and comprises a sleeve |56 and'more snugly piloted at its periph-- series of circumferentially spaced fingers |65 extending through circumferentlally spaced apertures |66 in the pulley face |6| and apertures |61 in the pulley face |53. 'Ihe inwardly bent ends of fingers |65 are projected over a snap ring |68 surrounding the cylindrical housing portion of the pulley face |53, and are clamped, so as to attach the cage |64 to the pulley face |53, by a are a plurality ofequalizer arms |13, preferably three in number and equally spaced around the cage |64, which are groved at |18 to provide bearing grooves for the fulcrum edges, and apertured-at |15 to permit a linger G65 of the cage to pass through. The curved outermost ends of these arms engage the back side oi the pulley face |6| and are restrained against circumferential and axial movement relative to the pulley face by' nngers |16 and |11 which form a part of the pulley face and which are bent over the sides of the equalizer arms |13 to permit vfree radial movementof the ends of the arms along the pulley face. Shoes |1801 abrasion-resistant sheet metal are retained by the ngers |16 and |11 and interposed between the ends of the equalizer arms and the back of the pulley' face |6| to permit relative sliding motion of these parts without lubrication. 'I'he innermost ends of the equalizer arms |13 bear against the frusto-conical end of a, member |88 which is slidably mounted on the countershaft 48. Hardened steel rings |8| are pressed into the member |88 to provide bearing vsurfaces in contact with the countershaft. The member |88 is urged in the direction of the equalizer arms |13 by resilient means, preferably comprising two 4compression springs |82 and |83 'of diierent pitch diameters positioned in the space surrounding the cylindricalportion of member |86 and within the sleeve |56, andbearing at one end against the member `|88 and at the other end against a Washer |84 which abuts diametrically opposed adjusting screws |85 and |86 threadedthrough the hub |55. Bymeans'of the adjusting screws |85 anc'rl`l86 the compression of the springs |82 and |83 may be changed.l

It is evident that the force of the springs |82 and |83 acting through the member |88 against the inner ends of the equalizer arms |13 keeps these arms in firm engagement with the fulcrum edges 1| at all times and results in the outer ends of the arms |13 exerting a force onthe pulley face |6| tending to move it toward the opposed face |53. Since vall three arms 13 are acted upon equally, force is evenly applied to the ery by the shoulder |88 of the pulley face member |53. Between the ramp |81 and the pulley face |53 a marcel'sprlng |90 is compressed so that it has a slight tendency to move the ramp |81 toward lthe opposed ramp |62. Confined between the opposed ramps |62 and |81 is a plurality of steel balls |8| which engage the ramps |62 and |81 on either side. The ramps |62 and |81 are so shaped that the axial separation therebetween diminishes with increasing distance from the countershaft 48, and so that they never open far enough apart-to permit the balls 16| face |53. thus bringing the ramps E62 and 18T nearer together and reducing the diameter of pulley face |6| and the. entirepulley face is to pass out of coniinement between the ramps. The tendency of the springs |82 and |83 is to cause the pulley face |6| to vapproach the pulley the circle of balls `|9|. The balls 9| are preferably of'such diameter and in such number that when the unit 46 is not in rotation the balls lie in an annular ring closely around the sleeve |56 `with each ball lightly pressed against the adjacent balls by'the tendency of the two ramps to approach one another. Rotation of the unit 86 with it the pulley face I6 away from the pulley face |53 to a point where the increased force of springs E82 and |83 is sufficient to balance the centrifugal force on the balls |9I. When the countershaft 48 is rotating, then, the position of the pulley face |6| relative to pulley face |53 is determined by the centrifugal force on the balls |9l which in turn isa measurel of the speed of rotation of the countershaft, or the speed of the vehicle.

The operation of the countershaft unit 66 in cooperation with the clutch and pulley unit and the V-belt 41 as an automatic transmission will now be considered. If the springs |82 and |83 are substantially compressed by inward adjustment of the screws |85 and |88, they preferably exert suilicient force in their extended position to urge the pulley face |6| toward the pulley. face |53 with a greater force than that with which the pulley lface is urged toward the pulley face I8 by the springs |22 and |23 when in their compressed position. Therefore, when the vehicle is in slow motion and the units 45 and 46 are rotating, the pulley face v|6| will be moved to the closest permissible position relative to the pulley face |53, being limited by abutment of the inner ends of the arms |13 with the cage |64, or by.

the belt 41 coming to the position of minimal l pitch diameter on the unit 45. The belt 41 will be forced to near the outer periphery of the pulley faces |53 and ISI, causing it at the same time to move inwardly between'the pulley faces ||l and of unit 45 to occupy a position close to the pulley hub |08, and forcing the pulley face away from the pulley face against the force of the springs |22 and |23. Under these circumstances the transmission is in low gear: that is, it is in a condition wherein it provides the greatest ratio between engine speed and countershaft speed, or between engine speed and wheel speed. I

If the throttle of engine 4| be opened and the vehicle started forward by engagement of the clutch, the Vvehicle will move forward in this low gear position. As the wheel speed increases, increase in rotational velocity of the countershaft 48 will subject the balls |8| to centrifugal force which will cause them to move outward against v the parts may occupy positions as illustrated in Fig. 3, in which the ratio of engine speed to wheel speed has been reduced from that corresponding to the low gear condition.

Still further increase in wheel speed will result in further increase in centrifugal force on the balls i9 l with resultant increase of the axial force tending to separate the pulley faces of the countershaft unit dii. This permits the belt 1 to be brought to a smaller pitch diameter on the unit i6 and to a larger pitch diameter on the unit 45, thus still further reducing the effective transmission ratio. 'When the wheelspeed becomes sufliciently great, the pulley face i6! will be displaced to the position of greatest permissible separation in which the member 486 abuts the washer M9 and the belt @l lies adjacent the ilngers E65 on unit t@ and close to the periphery of pulley faces lili and iii of unit 45, the transmission then being in the condition providing the smallest permissible ratio of engine speed to wheel speed, that is, in high gear condition.

It is evident that when the vehicle slows down, relative motion of the various parts will occur in the reverse direction and, when the vehicle comes to a standstill, the belt il will again be in the position of greatest permissible pitch diameter on the countershaft unit and the balls @6l will again bevretracted to their smallest pitch circle. It will also be apparent that the speed at which the 'centrifugal force on the balls 89| first overcomes the resultant spring force and produces shifting of the speed ratio of the transmission and the speed at which the transmission nally reaches the high gear condition may be adjusted by moving'the screws 85 and |36 inwardly to increase the initial load upon the springs E82 and l83, or outwardly to reduce this initial tension. The transmission may thus be adjusted as desired to various road, load and driving conditions, and by proper proportioning of the parts, almost any type of variation of the effective transmission ratio as a function of vehicle speed may be obtained.

`While the foregoing description of the operation of the transmission explains the manner in which it changes the transmission ratio in response to vehicle speed, the transmission is preferably also adapted to vary the transmission ratio as the engine torque changes, in such manner as to render the overall performance of the transmission much more suitable for propulsion of motor vehicles than if ratio change were determined solely by vehicle speed. The variation of transmission ratio with engine torque is principally a result of the positions assumed by the belt 41 relative to the pulleys of the units 45 and 46 when torque is being transmitted.

In the diagrammatic illustration of Fig. l', the vehicle wheel 42 is represented as resting on the ground 49 and is driven from the counteraeeogres is indicated by the arrow. In this view, the belt 4l is represented in an intermediate position about one-third the way from the position of minimal pitch diameter on unit 45, represented in Fig. ll, to the position of maximal pitch diameter on unit 45, represented in Fig. 12. Preferably the springs H22 and |23 in the unit 45, and the springs E82 and |83 in the unit 46 are so proportioned and adjusted that they balance one another in their effect upon the transmission when the belt is approximately in the position represented in Fig. 10, and the vehicle is at rest or travelling at low speed, in such manner as to make this belt position one of equilibrium. 1n Fig. l0, if torque is being exerted by the engine in the direction indicated by the arrow, the belt Q1 will be under tension on the left side, as shown, and will be relatively slack on the right side and may even loop outward as indicated by the dotted lines. With this belt condition, as rotation progresses, the taut side of the belt will tend to creep to a smaller pitch diameter where it feeds into the pulley of unit 45. At the same time, the relative slack in the right side of the belt will permit this portion to creep to a larger pitch diameter on the countershaft unit 46. Depending upon the balance of forces involved, the degree to which the belt leaves the normal position of Fig. 10 may vary over a wide range. One balance of forces which gives very desirable results in the type of vehicle under consideration is that in which movement of the vehicle at lowspeed through a distance of a few feet under full engine torque or clutch slipping torque will cause a shift of the belt into the position shown in Fig. 11, representing the extreme low gear position. This position is one which the transmission will automatically assume if the vehicle encounters road resistance such as to slow it down to the point that the centrifugal balls in the countershaft pulley exert little or noaxial force.

shaft unit 46 by the chain 53. The belt 41 connects the clutch and pulley unit '45 with the countershaft unit 46. The vdirection of rotation Since the transmission under these conditions would be expected to assume the position of Fig. 10, which is determined solely by balance of opposed spring forces, the additional and very substantial increase in overall reduction gained .by the creeping of the belt into the position of Fig. l1 gives the vehicle greatly improved hill climbing characteristics.

If the vehicle .is at rest with the transmission in the balanced position of Fig. 10 and the throttle is slowly opened and the vehicle gradually accelerated and brought up to speed, the creeping tendency just described will be largely minimized since the belt tension will be low and the forces tending to cause creeping will be proportionally low. In this case the vehicle will start forward in what may be termed an intermediate ratio and as road speed increases and the centrifugal forces on the balls in the countershaft unit 46 result in axial force on the movable pulley face of this unit, the transmission will shift into the position shown in Fig. 12. If, however, from a. static position, as in Fig. l0, the vehicle is rapidly accelerated by full opening of the throttle, the relatively high belt tension will result in rapid creep into the position of Fig. 1l in the rst few feet of forward movement, andeven at-low road speed the engine may rotate at such a speed that it delivers its maximal power output. This permits most,

speed creates such centrifugal force on the balls of the countershaft unit d6 that gradual shifting of the transmission ratio occurs, the shifting of ratio continuing with increase -of wheel, speed until the transmission is again in the position shown in Fig. 12. lt will thus be seen that for' hill climbing or maximal acceleration the transmission Will automatically assume the lowest posl sible gear (highest ratio of engine speed to wheel speed) at low wheel speed and will permit utilization of full engine power atthese speeds. If, however, conditions make it unnecessary or undesirable to accelerate the vehicle as rapidly as possible, it may he accelerated more gradually will cause ,the belt to seek asmaller pitch. circle on the pulley of the countershaft unit d6 and a larger pitch circle on the pulley of the unit 35,

thus increasing the mechanical advantage and diminishing the force necessary to push the verf hicle ahead. Ordinarily the engine will vstart in Y three or four turns before the effect of creep has caused much change in ratio, but if for any reason the engine fails to readily start, the de`= crease in ratio of engine speed to wheel speed caused by continuing creep, with resultant decrease in edort required to push the vehicle, is a pronounced advantage.

The manner in which belt creep permits adn vantageous change of transmission ratio in re spouse to torque conditions independent of wheel speed, depends upon the face angles oi the v pulleys and belt, the particular pitch diameter Aat which the belt is operated on each pulley, the load ing upon Whether the throttle is iully or only f partly opened. If the operator of the vehicle desires that it should be ready to start immediately in the extreme low gear position, thus permitting maximal acceleration for starting from the standing position, he may anticipate his desire by bringing the vehicle to a stop with the throttle partly opened,T using the brake, if necessary, to stop the vehicle.. When this is done the transmission will be subject to a forward driving torque while the vehicle is being stopped and will shift into the extreme'low position in the same manner it would upon encountering any other type of tract'ive resistance.

It is clear that if the vehicle is operating at high wheel speed with the belt 4'! in a position exerted by the ,springs tending to force the pulley faces together, and upon the force constants 'of l these springs. These factors may be Avaried over a wide range to increase or diminish or vary the character of the response to torque.

ln the embodiment of my invention illustrated herein, a further control' element has been introduced in the construction to accentuate the creeping tendency of the belt under certain conditions of operation and to reduce'it under certain other conditions, thus further improving vehicle performance. Reference to Figs. 3, 6, and 'I will show that the torque link springs H5 of the unit 45 are normally installed so that they are under compression when driving torque, applied to the housing II'I by the pulley hub Hi8, is transmitted through the posts IIB into 2 the springs H5. It will be clear that when the of maximal pitch diameter on'the pulley of the l unit 45, as shown in Fig. l2, and the direction of applied torque is as indicated by the arrow, a slack loop will under these conditions appear on the right side of the belt. The amount of slackl which appears in this loop depends upon belt ten sion or engine torque. Under light engine loads,

little'slack will appear, but under conditions ofy effective pitchdiameter on'the pulley of the unit will cause a change .in the transmission ratio to increase the mechanical advantage of the engine.

Another manner inwhich the creeping tendency of the belt is utilized, in this c ase to improve the ease with which the vehicle may be started by pushing it forward, is shown. in Fig. 13. 'This iigure presents the condition which exists when the vehicle has previously come to rest with the pulleys and belt in the balanced position of Fig.'v

l0, and is then being pushed forward with the engine at rest. Applied torque `is as indicated by the arrow and'the right side of the belt is now under tension and 4the left side of the belt exhibits a certain amount of slack. As soon as the engine starts torotate, the creeping tendency springs H5 are angularly disposed relative to the plane of rotation of the unit,.the compressive force in the springs H5 under forward driving,

torque will have an axial component tending to move the pulley face I II' in an axial direction which is dependent upon whether the springs i I5 diverge at an angle to the left or to the right from the plane of rotation. The parts of the unit 45 are preferably so proportioned and positioned relative to one another that the springs II5 lie parallel to the plane of rotation when the movable pulley face I I6 occupies a position consistentvwith the position of the belt in Fig. 10. When the pulley face III is moved to the right i'rom'this'position toward the condition represented in Fig. 1l, the axial-component of the 'force of springs I I5 vis such as to move the movable face I II still farther to the right; while if the pulley face I I I is moved to the left from the normal position, the axial component of the force of springs H5 is in sucha direction as to move Vthe pulley face still farther to the left.

Reconsideration now of the creeping of the belt at low speed and high torque from thebalanced position of Fig. 10 to the extreme low gear position of Fig. 11, will show that the increasing axial component of the forfce of'springs II 5 as j the pulley faces separate tends to augment the creeping effect and to make the transmission shift into extreme low gear more rapidly with increase of torque. Similar analysis of the creeping tendency, which will exist under increase ofv torque inthe high speed range, will show that the axial force of the torque links IIS is opposed to the normal creeping tendency so that the change of transmission ratio under increase of throttle when the transmission is in nigh speed positions is less than it woum be if the torque were transmitted through a straight llrey and key-way or other device which is ree of axial reaction as a function ci torque. it will be evident, then, that under low speeds and severe conditions of pulling, the mechanism is more responsive in transmission ratio change to increase of tractive eiort and increase of engine torque than in the high speed rame. In a vehicle where the power is limited and it is important to obtain maximal hill climbing characteristics and maximal tractive eort atV low speed, the advantage of such an arrangement is obvious.

Figs. li and l present curves illustrating the performance of the transmission ci my invention when adapted to one speciilc application'. in this application a Johnson 230i iron Horse7 engine was used. Curve 200 shows the manner in which the torque of this engine varies with engine speed, and curve Ztl shows the manner in which the engine horsepower varies with engine speed. it will be noted that the engine has A a maximal torque of about 29 pounds-inches at i700 R.. P. ild., and a maximal horsepower or 1.@ at about 2500 R. P. lill. Curve 202.? shows the manner in which the ratio of engnie speed to wheel speed in the particular application under consideration varies in response only to vehicle speed. This curve starts from an intermediate ratio of 8.5 to l, corresponding to the balanced position of the l-belt on. the pulleys with the vehicle stationary, as shown in Fig. l0, and ree mains at this ratio until the vehicle speed is about 5 miles per hour, beyond which the ratio gradually decreases to a value of about 2.75 to l at 30 miles per hour. The curve 202 thenpresents what might be termed the no load change of ratio which would be obtained ii the vehicle could be accelerated from a standing position to its maximum speed without actual application ci driving torque or building up of tension on the il-belt.

Curve 203 shows the manner in which the change in transmission ratio takes place under full engine torque, assuming that the vehicle starts with the transmission in the extreme low gear'position. Under these conditions the transmission ratio will start at about l2 to l and remain at this value until the vehicle attains a speed of about 5 miles per hour. When this speed is reached,` the centrifugal forces acting upon the unit 43 will induce a. change of transmission ratio, and if the vehicle proceeds under full throttle, the change of ratio will be complete at about 30 miles per hour and the nal high speed ratio will be about 3 to 1. The displacement of the curve 203 from the curve 202 is a reflection of the change in transmission ratio produced by the previously discussed creeping tendency of the belt.

Curve 204 shows the transmission curve corresponding to a. start under full throttle from Vthe intermediate balanced ratio position illustratedl in Fig. 10. It will be notedthat the ratio o! engine speed to wheel speed increases rapidly while the vehicle is being accelerated to 5 miles per hour, beyond which if acceleration is continued under full throttle operation, the -ratio change, of course, follows that of curve 203.

It will beevident that operation of the vehicle with partial throttle openings would be indicated by curves lying between curves 202 and 203, and that a typical curve for ratio change under moderate acceleration might be one such as curve 205. v

Curve 213 represents the variation oi engine speed with vehicle speed under conditions corresponding to the maximal acceleration curve 203, and may be understood from the following description of the action taking place. The engine under consideration has a normal idling range of from 800 to 1050 R. P. clutch is adjusted to start engagement at an engine speed o approximately 1100 R. P. M. Following engagement of the clutch, the engine speed stays at about this value until the vehicle speed has reached about 3 miles per hour. During this period the clutch at first slips considerably, but as the bpeed of the vehicle approaches 3 miles per ur, the slipping diminishes and slight increase in vehicle speed above 3 miles per hour then permits the engine to accelerate with almost no slip, the clutch iinally locking in at 'about 1400 R. l?. M. and fi miles per hour. From i miles per hour to a speed of about 8 miles per hour, engine speed varies almost directly as ve-` lucie speed. It will be noted that this portion or" the curve 20% is practically a straight line and that in the corresponding portion oi curve 203 there is very little change in ratio. When vehicle speed reaches 8 or 9 miles per hour, relatively rapid change of ratio occurs with the result that, although the vehicle accelerates rapidly to a much greater speed, Athere is only a small increase in engine speed; When the ve= hicle reaches a speed of' about l2 miles per hour, the change of transmission ratio continues according to such a function of increasing vehicle speed that the engine speed remains substantially constant at 2500 R. P. M. and full engine power is available ior acceleration up to crease in vehicle speed above 30 miles per hour With the particular adjustment of transmission vand the particular chain and. sprocket combination employed in the application under consideration, the transmission completes its shift into the high. gear position at about 30 miles per hour, and from that point on any increase in vehicle speed leaves the ratio unchanged. Increase in vehicle speed about 30 miles per hour thereiore necessitates increase in engine speed, as indicated by the oblique upper portion or" the curve 200, but in a small vehicle of the size and weight propelled by an engine such as that in the application under consideration, such speeds are normally not attainable on the level, and this possible increase of engine speed above the point at which the horsepower curve peaks is obtainable only when running down hill.

Curve`20l represents the variation of engine speed with vehicle speed under the no load condition corresponding to the curve 202.' This curve shows the same general response of engine speed to change of vehicle speed, but it will be noted that for any vehicle speed, the correspondlng speed of the engine under no load condition is appreciably lower. This permits a great increase in life of the engine and reduction of maintenance costs if the operator chooses to use only partial throttle opening during acceleration. By appropriate change of the curvatures of the ball ramp in the countershaft unit I6, it is possible, if desired, to delay the point at which change of 4ratio from normal extreme low gear position commences until the peak of the power curve is reached at 2500 R. P. M., and then to introduce-'a rapid change of ratio to hold the engine. speed at this peak value at higher road speeds. 'Ihe engine speed versus vehicle speed curve for such a construction is indicated bv M. and thethe dashed curve 288 where it diverges from the curve 2536.

If it be considered that the curve 206 represents the perfomance which wouldy be obtained with the springs |82 and |83 of t e countershaft unit 66 in the position of intermediate adjustmentaforded by screwing the screws |85 and 85 inward a distance equal to half their threaded length, then retracting these screws to their extreme rightward position as seen in Fig. 3

would result in an engine speed versus vehicle speed curve as indicated by the line 209, the lower and upper portions of which merge into the curve 2d?. Conversely, maximal initial compression of the springs achieved by screwing the adjusting screws ld and ist inward the full threaded length, would result in an engine speed versus vehicle speed curve as suggested by the curve 2id. It is evident that this adjustment, which is under the control of the operator, permits the operator of the machine to adjust the effective transmission ratio to suitl his individual needs. A lightweight rider, for instance, might use the adjustment indicated by curve 2IS, while a. heavyweight rider might prefer the adjustment indicated by the curve 2li).

In vehicles in rental service orin messenger and delivery service where the operators might be inclined to ride the vehicles more or less continuously at maximal speeds and maximal throttle openings, excessive strain on the engine may be avoided by substituting for the ball ramps |62 and |81 of the countershaft unit 45, ramps having less curvature. If the ramps are modied in this manner, the curve of engine speed versus vehicle speed at full throttle opening may be modied in the manner of .curve 2| I.V It will be noted that a curve of this sort permits use of peak engine power for maximal perfomance both in acceleration and in hill climbing at low versus vehicle Speed curve 206 will be modified as suggested by the curve 2 I2.

It is understood that the performance curves discussed above are peculiar to one particular type of engine with its individual horsepower and torque characteristics. vIn a group of engines of presumably identical characteristics, some variation in performance at different speeds will often or usually appear. It is obvious that the individual adjustment made possible by the construction of the transmission of my invention permits substantial modification of transmission characteristics to obtain the best possible performance or the most desirable performance from any particular engine. 'It should also be noted that the overall response of the transmission to tractive eort, engine torque, and vehicle speed is modined by the reduction ratio of the sprocket and chain employed and by the total load and force constants of the springs |22 and v|23 in the unit 65. Change of sprocket ratio will have the general effect of increasing or reducing the milesv per hour scale of the charts of Figs. 14 and 15.

Change of the total load or force constants of lthe springs |22 and |23 is equivalent to change and special provision is made to permit adjustor moderate vehicle speeds, but when the vehicle speedreaches approximately 20 miles per hour,

the ratio change of thetransmission becomes progressively greater so that the engine actually slows down with increase of vehicle speed. This means that the engine is held at a speed below the one at which it delivers maximal power, and the normal high speed of the vehicle on a level road is somewhat reduced. Y' This slight reduc- Consideration of the engine torque curve 2M will showthat engagement of the clutch begins at a point substantially below the speed at which the engine develops maximal torque. This means that during the rst portion of the starting and acceleratlng period, the tractive effort is not as great as it would be if greater engine torque could be applied at any particular ratio. If it is important that maximal starting performance of the vehicle be attainable, the tension of the grommet spring |30 in the unit 45 may be increased or the weight of the spring may be reduced by removal of a portion/of the ller spring IBI, by substitution of a llr spring of lighter weight or by total elimination of the flllerspring, and the clutch will accordingly not begin to engage until a relatively high engine speed has been attained. If the clutch be modified in this manner, kthe low speed portion of the engine` speed ment of the transmission to compensate for belt wear.

When a new v-belt is used in the transmission, it will be found that when the belt is occupying the extreme low gear position in -which it has the minimal pitch diameter on unit 45, the width o'f the new belt is such as to prevent the pulley face |6| of unit 48 from coming into the extreme rightward or closed position characteristic of the low gear condition with a used belt. In this position of the pulley face ISI, the ball ramps |52 and |81 may not be pressed together sulciently to retract the balls |8| into a circle of minimal diameter in which each ball touches the adjacent ones. Since, under these conditions', the balls |9| might'be loose between the ramps |82 and |81 and havea tendency to rattle when the speed of rotation is so low that centrifugal force is in- 4sufcient to overcome the force of gravity on the balls, the marcel spring interposed between the ramp |81 and the housing portion of the pulley face |58 is depended upon to force the ramp |81 toward the ramp |62 and in this manner take up any slack between the balls and the ramp. 'I'he balls |8| are thus properly centralized on the minimal pitch circle until such time as centrifugalitorce enables them to first' compress the marcel spring and then separate the pulley faces by direct pressure upon the-ramps.

In the high gear position, the belt 41 has its minimal pitch diameter on the u nit 48 and the to accommodate the new belt inthe position of associated parts.

Y aaeogae minimal pitch diameter. As the belt diminishes in width due to wear, it may seat more deeply in the pulley oi unit it and eventually bear against the ngers |25, and for this reason the fingers |65 have edges so formed that the belt may run against them without damage. If the power transmitted by the belt is relatively light, it may be transferred from the inner face of the belt 41 to the fingers |65 without abnormal slip, even though at high speeds the centrifugal action of the balls |9| against the ramps 22 and itl may separate the pulley faces itl' and |53 so far that no appreciable side contact is made against the belt di. If the power being transmitted is high, however, the flat Contact of the belt against the ngers may be insuicient to transmit this power without undue slip, and it may become necessary to restore the side contact oi' the pulley faces against the belt. This is done by turning the screw 59 inward so that it moves the key ll leftward in Fig` 3 and establishes a newlimiting position for rightward travel oi the member 43B. This adjustment may be easily made by the operator of the vehicle whenever the engine gives vaudible evidence of racing when the machine is travelling at high speed.

Y In Fig. 16 I show an alternative form or the unit dit in which means are provided for making the transmission rati'o responsive to the vacuum created in the engine intake. In this case the countershait unit d@ is mounted on `a countershaft 222 which, except for the end portion upon which the -unit l is mounted, is similar to thel countershait it in the apparatus previously cle-Y scribed, ancl is similarly connected with the other inFig. 16 the'hub 221 takes the place of the hub 155 in the previously described unit.` and is connected for rotation with the countershat 224i by means of a key 222. The hub 22| is retained on the countershaft by snap ring itl) engaging a groove on the countershaft. The springs i 32 and i855 act at one end on the member l2@ and at the other end on 'a washer 223 which abuts the adjusting screws |85 and it and is turned inwardly to pilot on the hub 22 l Surrounding the spring |83 and clamped between the spring 183 and the-abutting surfaces at either end thereof, is a cylindrical sheet 224 ofrleaible material, such as rubber, composition, or fabric, which forms with the supporting spring |83 an air-tight bellows providing a chamber within. The countershaft 222 has an axial bore 225 extending part way from its outer end, and communicating with the bore 225 and the chamthe vacuum control valve.

In the form of the unit shown ber within the bellows 224 is a passage 226. A

tting 221 has a cylindrical portion 228 fitting the bore 225 so as to permit the countershaft 220 to rotate while the tting 221 remains stationary. A passage 230 connects with the bore 225 at one end and at the other end with suitable conduit means leading to the intake of the engine 4| in such manner that a vacuum is produced within the bellows 224 by operation of the engine 4I. In order to penmit compensation for Wearing 'of the belt, the movable pulley face is made in two parts, the inner portion 23| being attached to the ramp |62 for piloting on the sleeve |56 in the same manner in which the movable pulley face |6| was connected thereto in the form of the unit previously described. The outer inclined portion 232 which is adapted to contact the belt 41 is attached 233 which are threaded through the portion 23| such manner that the screws 233 may turn within the portion 232. It will be clear that with this construction the pulley face 232 may, for any position of the portion 23|, be moved toward or away from the pulley face |53 as may be necessary t0 compensate for diierent widths of belt. The remaining parts of the unit et may be constructed as previously described in connection with the unit illustrated in Fig. 3.

The operation of the unit as illustrated in Fig. 16 is similar to the operation of the previously described unit of Fig. 3, except that in the unit of Fig. 16, the position of the movable pulley face 232 is changed 'as the degree of vacuum produced by the engine changes. The vacuum within the bellows 22d tends to counteract the compressive force of the springs '22 and 683, so that the greater the degree of vacuum, the more the pulley iace 232 will be moved away from the opposing pulley face i553 and the more the transmission will be shifted toward the high gear condition. 'Ihe degree of vacuum produced by the engine is dependent upon the throttle opening and the speed of the engine, increasing with thespeed,

and decreasing as the Athrottle is opened. The Vacuum produced within the bellows 226| may be further modided by a valve in the conduit connesting passage 222 with the engine intake.

It will be evident that many diierent eects may be secured by adjustment of the screws l and lllli to vary the compression oi the springs l2?. and |23, and by varying the adjustment of One desirable condition is that in which the belt '@l'l occupies an invtermediate position ori-the pulley or" unit #l5 when Under these circumthe engine il is idling. stances the compremive force of the springs |532 and |23 is partially balanced by the vacuum within the bellows 222, and when the engine throttle is opened to accelerate the vehicle, the degree of vacuum within the bellows 22dis lessened, permitting the springs 32 and |83 to act on the l equalizerarms 113 to move the pulley face 232 closer to the opposing pulley face |53 and quickly bring the transmission into low gear'position. As the speed of the vehicle builds up and less throttle opening is required, the degree of Vacuum Within the bellows 226 will increase and assist the centrifugal action of the unit in bringing the movable pulley face 232 to the extreme high gear position.

While I have disclosed my transmission in connection with a three-wheeled vehicle, it will be understood that the transmission may be ernployed in the propulsion of a two-wheeled vehicle, which,'for example, may be of the general type disclosed in the patent application of Howard B.

, Lewis, Bruce Burns, Austin E. Elmore, and Esley and are riveted to the portion 232 as at 23e in 75 F. Salsbury, Serial No. 202,868, now matured into Patent No. 2,225,914, issued Dec. 24, 1940 or in any other suitable form of vehicle. It will also be understood that various variations .or modications in design or construction of the parts of the apparatus of my invention other than those disclosed herein may be made by those skilled in the art Awithout departing from the spirit and scope ofthe appended claims.

From the above it will be obvious that' I have invented a novel power transmission for transmitting power from a driving shaft, such as the engine shaft, to a driven shaft, such as the countershaft, which consists of the driving pulley assembly shown at 45, the driven pulley shown at 46 in Fig. 14, and the V-belt 41 through which the pul1ey"45 drives the pulley 46. The driving pulley 45 consists of the conoidal members H9 and ill the member Ill being movable axially to vary the ei'ective diameter of the pulley 45 and being operated by the springs l2@ and t28 which tend to force the pulley le into a positi n giving the pulley i5 its maximum diameter. e driven pulley te consists of conoidal members |53 and ISI, the member l5@ being free to move ly to change the effectivev diameter of the pulley 66. The members 53 and del are forced apart to decrease the effective diameter of the pulley d@ by the centrifugal force of the balls im, this force, of course, being generated by thevrotation oi the driven shaft i3d. The V-belt @l transmits power from the pulley da to the vpulley ed.

I claim as my invention:

l. In power transmission apparatus, the oombination of: a shaft; a pulley hub supported rotatably on said shaft; a pulley face attached to said pulley hub; a second pulley face slldablyv and rotatably mounted on said pulley hub, said pulley faces providing opposed inclined surfaces for engagement of a V-belt therewith; a housing attached to said pulley hub a compression spring disposed between said housing and said secondV pulley face urging said second pulley face toward said iirst pulley face; and a plurality of circumferentially spaced links connecting said housing and said second pulley face, each of said links comprising a loop of resilient material at one end pivotally connected to said housing and at the other end pivotally connected to said second pulley face. l

2. In power transmission apparatus, the combination of: 'a pulley having opposed inclined faces of said pulley being axially movable relative to the other for varying the pitch diameter of said belt on said pulley; means resillently urging said movable pulley face toward the other of said pulley faces; a ramp attached to said movable. pulley face; a second ramp opposed to said rst ramp and limited in amal movement in a direction away from said first ramp, said ramps being so shaped that the axial separation therebetween diminishes with increasing radius; and masses `disposed inthe annular space between said ramps and adapted to be acted uponby centrifugal force resulting from rotation of said said fingers projecting through said apertures and being attached to said other of said pulley faces;

an axially movable member surrounding said shaft;` a plurality of arms p ivoted on said cage and movable in the slots between said lingers, said .arms bearing at their Vouter ends against said movable pulley face and at their inner ends against said member; a spring bearing at one end against an axially fixed abutment and at the other end bearing against said member to urge said member toward said arms; a ramp-attached to said movable pulley face; a second ramp opposed to said first ramp and limited in axial aaedvcs i .faces for engagement .with a V-belt, one of the movement `in a 'direction away from said iii-st ramp, said ramps being so shaped that the axial separation therebetween diminishes with increasing radius: and a plurality of balls disposed in the annular space between said ramps and adapted to be acted upon by centrifugal force resulting from rotation of said pulley to throw said balls outwardly and increase the axial separation between'said pulley faces.

4. In power transmission apparatus, the combination of: a shaft; a pulley mounted on said shaft and having opposed inclined faces forengagement with a V-belt, one of the faces of said pulley being axially movable relative to the other for varying the pitch diameter of said belt on said pulley;- an axially retained member provid ing fulcrum edges; a plurality of arms pivoted on said fulcrum edges, said arms bearing at their outer ends against said movable pulley face: an axially movable member surrounding said shaft and being in engagement with the inner ends oi said arms; a spring bearing at one end against an axially ixed abutment and at the othex` end against said member, in such manner that the compressive force of said spring acts through said axially movable member and said arms to move said movable face toward the other of said pulley faces; means for adjusting the axial position of said abutment; aramp attached to said movable pulley face; a second ramp opposed to'said first diminishes with increasing radius; and a pluralityof balls disposed in the annular space between said ramps and adapted to be acted upon by centrifugal force resultingv from rotation of said pulley .to throw said balls outwardly and increase the axial separation between said pulley faces.

5. Inpower transmission apparatus, the combination of: a shaft having a slot in the. .end thereof; a pulley mounted on said shaft and having opposed inclined facesfor engagement with a V-belt, one of the faces of said pulley being axially movable relative to the other for varying the pitch diameter of said belt on said pulley; a key fitting in said slot and connecting said pulley to said shaft for rotation therewith; an axially movable membersurrounding said shaft; means adjustably limiting the travel in one direction of said axially movable member including'said key vand a screw in threaded engagement with said edges, said arms bearing at their outer ends against said movable pulley face and at their inner ends against said axially movable member; a pair of opposed .annular ramps so shaped that the axial separation therebetween diminishes with increasing radius, said ramps being disposed between said pulley faces; and a plurality of balls disposed in the annular space between said ramps and adapted to be acted upon by centrifugal force resulting from rotationof said pulley to throw said balls-butwarcllyI and increase the axial separation between said pulley faces.

6. In power transmission apparatus, the combination. ofi a shaft; ay pulley mounted on said shaft comprising two pulley faces providing` opposed inclined faces forengagement with a V- belt, one of said pulley faces being axially movable relative to the otherl loi said pulley faces for varying the pitch diameter of said belt on said pulley; means resillently urging, said movable 1o l pulley face toward the other of said pulley faces;

- a sleeve surrounding said shaft and attached to the other-of said pulley faces; two opposed ramps slidable on said sleeve and disposed between said pulley faces, said ramps being so shaped that the axial separation therebetween diminishes with increasing radius; a plurality of balls disposed in the annular space between said ramps and around nation of: a pulley comprising two pulley faces l providing opposed inclined surfaces for engagement with a V-belt, one of said pulley faces being 2,260,795 rality of circumferentially spaced links between said housing and said movable pulley face, each of said links comprising a loop of resilient material pivotally connected at one end to said housing and at the other end tosaid movable pulley face; a. V-belt disposed between said pulley faces and in engagement therewith; two opposed pulley faces mounted on saiddriven shaft and connected for rotation therewith providing opposed inclined surfaces in engagement with said belt, Y one of the pulley faces on said driven shaft being axially movable relative to the opposing pulley face; spring means urging the movable pulley face on said driven shaft toward the opposing axially movable relative to the other for varying the pitch diameter of said belt on said pulley; means resiliently urging said movable face toward the other of said pulley faces; two opposed annu-l lar ramps disposed between said puiley'faces, said ramps being so shaped that the axial separation therebetween diminishes with increasing radius; masses disposed in the annular space between said ramps and adapted to be acted upon by centrifugal force resulting from rotation of said pulley to throw said masses outwardly and increase the axial separation between said pulley faces; and means responsive to the vacuum in the pulley face, said spring means being of such strength relative to said rst mentioned spring as to cause said belt when at rest and under substantially no load condition to assume a position on said pulley faces intermediate between the extreme permissible positions thereon, said links being adapted under these conditions to lie subintake of said engine and acting in opposition to said means resiliently urging said movable pulley face toward the other of .said pulley faces.

8. In power transmission apparatus associated with an internal combustion engine, the combination of: a shaft; a pulley mounted on said shaft stantially in a plane parallel to the plane of rotation; and centrifugal means associated with said driven shaft adapted to increase the separation between the pulley faces associated with y said driven shaft upon increasing speed of rotation of said driven shaft. l

10. Automatic power transmission apparatus comprising in combination: a driving shaft; an axially movable member mounted to rotate about i the axis of said driving shaft; means connected for rotation with said driving shaft and providing a surface on one side of said member for engagement therewith and a ramp on the other side of said member extending toward said member as it proceeds outwardly from said axis; a plate posiand comprising two opposed pulley faces provida ing opposed inclined surfaces for engagement with a V-belt, one of said faces being axially Vmovable relative to the other of said faces for varying the pitch diameter of said belt on said pulley; two opposed annular ramps disposed between said pulley faces, said ramps being so shaped that the axial separation therebetween diminishes with increasing radius; a plurality of balls disposed inthe annular space between said ramps; an axially retained member providingY fulcrum edges; a plurality of' arms pivoted on said fulcrum edges and bearing at their outer ends against said movable pulley face; an axially movable member surrounding said shaft and bearing on the inner ends of said arms; a spring bearing at one end against said axially movable member and at the other end against an abutment xed relative to said other of said pulley faces, the action of said spring tending to move said movable pulley face toward said other of said pulley faces; a bellows connected between said axially movable member and said abutment providing a chamber within said bellows surrounding said shaft; and means connecting said' chamber with the intake of said engine for creating'a vacuum in said chamber.

9. In power transmission apparatus associated.

with a driving shaft and a driven shaft, the combination of: a pulley face mounted onandeonnectible for rotation with said-driving shaft; an opposing pulley face mounted for axial and rotativemovement relative to said first pulley fac,.

said pulley faces providing opposed inclined surfaces; a housing connected for rotation with said v first pulley face; a spring disposed in compression between said housing and said movable pulleyface for urging said movable pulley face toward said first mentioned pulley face; a plutioned between said ramp and said. member, said plate being connected to rotate Awith said ramp but being axially movable relative thereto; an extended annular coil spring disposed between said ramp and said plate, said spring being adapted to move outwardly in response to centrifugal force and by engagement with said ramp to move said plate into engagement with s aid member, and said member into engagement withsaid surface; means limiting the inward travel of said spring; a pulley face supported on said drivingv shaft and connected for rotation with said member; a second pulley face supported on said shaft and connected for rotation with said first pulley facebut axially movablerelative thereto, said pulley faces providing opposed inclined surfaces; spring means `urging said second pulley face toward said first pulley face; a V-belt disposed between said pulley faces and in -engagement therewith; a driven shaft; a pulley mounted on said driven shaft comprising two pulley faces providing opposed inclined surfaces in engagement with said belt, one of said pulley faces being axially movable relative to the other of said pulley faces; spring means urging the movable pulley face associated with said driven shaft toward the opposing pulley face; two opposed annular ramps disposed between said pulley faces associated with said driven shaft, said ramps being so shaped that the axial separation therebetween diminishes with increasing radius; a plurality of balls disposed inthe annular space between said ramps and adapted to be acted upon by centrifugal force resulting from rotation of said pulley to throw said balls'outwardly and increase the axial separation between the pulley faces associated with said driven shaft.

BRUCE BURNS.

Ionc'col'mnn, line 50,v for "Pully" read pulley-- CERTIFICATE or CORRECTION.

Patent No. 2,260,795. october 28, 19m.

BRUCE BURNS.

It is Ahereby certified. that error appears in the printed specification ofthe above numberedtpatent requiring correction as follows: Page' l, sec' I; page 5, second column, line 14.9, for "face 116" read ,--face '111; page 6, second column, line 5?, strike' out crease in vehicle speed 'above 50mi1-es per hour" and insert instead --the no1-mal mudmm of 50.1i1es per hour.-; and line 1 ;5 for "about" read above'; and that theV .said Letters Patent should 'De-read with this correction therein .that the same may conform to the record of the cese -in the Patent office. y

signed am sealed this 16th any or December, A.- D. 19in.

AHenry van Ars'dale,

(Seal) Acting Commissioner of Ptents. 

